<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style lang="css">
        .ball {
            width: 200px;
            height: 200px;
            /*  radial-gradient() CSS 函数创建一个图像，该图像由从原点辐射的两种或多种颜色之间的渐进过渡组成。它的形状可以是圆形或椭圆形*/
            background: radial-gradient(circle at 50% 120%, #ff0000, #800000);
            border-radius: 50%;
            box-shadow: 0 10px 20px rgba(0, 0, 0, 0.5);
        }
    </style>
</head>
<body>
<div class="ball"></div>
</body>
</html>
